Electric and hybrid vehicles typically include an alternating current (AC) electric motor which is driven by a direct current (DC) power source, such as a storage battery. Motor windings of the AC electric motor can be coupled to inverter module(s) which perform a rapid switching function to convert the DC power to AC power which drives the AC electric motor.
Many electric and hybrid vehicles implement an isolated high voltage DC bus which couples the inverter module(s) to the DC power source. Other modules, such as devices, components or circuits, can also be coupled to the high voltage DC bus. In some situations one of more of these modules can operate improperly and cause an electrical AC fault (ACF) to occur along the high voltage DC bus which causes high voltage spikes that can potentially damage other modules coupled to the high voltage DC bus.
One way to address ACFs is to implement a Ground Fault Interrupter (GFI) (sometimes also referred to as a residual current device (RCD), residual current circuit breaker (RCCB), ground fault circuit interrupter (GFCI)), that observes the respective currents at a ground terminal and a supply terminal, and disconnects a circuit coupled between these terminals when the differential current flow between these terminals is not balanced (i.e., zero (0)) since this signifies current leakage. Such ground fault detection circuits typically implement current transformers to detect ACF currents in the ground path. However, transformer-based ground fault detectors are expensive and bulky.
Another way to address ACFs is to implement ground fault detection using software algorithms. However, such software algorithms have long detection times.
Accordingly, it is desirable to provide a fast, simple, low cost and reliable ACF detection and/or verification circuit. It would also be desirable to provide a fast, simple, low cost and reliable ACF identification circuit which can aid in diagnosing the source of an ACF so that the source of the ACF can be turned off or disconnected from the high voltage DC bus when an ACF occurs. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.